Comment 5 for bug 1309802

I was going to add https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1319688 as a duplicate of this, thinking that the submitter of that bug was mixed up, and hadn't read the prompt carefully to see it was about config files. However, do-release-upgrade does actually prompt about some package add/removals, too, if I recall correctly, but I forget when.

 An attempt to let the whole install finish unattended would need to deal with that.